trans-Neptunian object

or trans·nep·tu·ni·an ob·ject

[ trans-nep-too-nee-uhn ob-jikt, ‐jekt, ‐tyoo‐, tranz ]
/ ˈtræns nɛpˈtu ni ən ˈɒb dʒɪkt, ‐dʒɛkt, ‐ˈtyu‐, ˈtrænz /

noun Astronomy.

any celestial object in our solar system whose orbit lies beyond Neptune, including Pluto: there may be some 70,000 trans-Neptunian objects orbiting 30–50 astronomical units from the sun, with diameters of at least 62 miles (100 km). Abbreviation: TNO

QUIZZES

THINK YOU’VE GOT A HANDLE ON THIS US STATE NICKNAME QUIZ?

Did you ever collect all those state quarters? Put them to good use on this quiz about curious state monikers and the facts around them.
Question 1 of 8
Mississippi’s nickname comes from the magnificent trees that grow there. What is it?

Origin of trans-Neptunian object

First recorded in 1920–25
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2020

Scientific definitions for trans-Neptunian object

trans-Neptunian object
[ trăns′nĕp-tōōnē-ən ]

A celestial object that orbits the sun at a greater distance on average than Neptune.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.